Electrochemical Cycling Stability Research Articles

Printed flexible supercapacitors utilizing composites of MWCNT/MOF ultrathin nanosheets: Exploring 1D/2D structural adjustment

The self-stacking propensity of metal–organic frameworks (MOFs) during synthesis, combined with their intrinsic limitations in electrical conductivity and mechanical stability, constrains their utility as high-capacity energy sources in wearable electronics. Here, we employ a surfactant-assisted method to mitigate the Z-axis stacking of zinc metalloporphyrin organic frameworks (NMOFs), yielding ultrathin two-dimensional (2D) material sheets. By integrating carboxyl multiwalled carbon nanotubes into these nanosheets (denoted as C-NMOF-x), the lamellar structure of MOF is preserved while promoting the formation of rich multistage micropores and continuous conductive channels. This structural refinement remarkably enhances electrochemical properties, including capacitance, electronic conductivity, and cycling stability. Leveraging synergistic interactions, the resulting C-NMOF-4 composite achieves a specific capacitance of 0.152 mAh/g in a three-electrode system at a current density of 1 A/g. Furthermore, the modulated C-NMOF-4 composites are successfully formulated into homogeneous e-inks suitable for dispensing printing, enabling the mass production of flexible micro-supercapacitors (MSCs). Notably, these MSCs maintain 95 % of their capacitance even after 180° bending under wearable conditions. This surface and interface microstructure modulation strategy holds promise for enhancing the synergistic coupling effects of 2D materials and offers new avenues for the application of innovative 2D materials in wearable electronics.

Facilitating Charge Transfer via Ti-Knot Pathway in Electrochromic Three-Dimensional Metalated Covalent Organic Frameworks.

Due to the ordered one-dimensional channel as well as accessible redox sites, two-dimensional covalent organic frameworks (2D COFs) have garnered extensive attention in the field of electrochromism. However, organic 2D frameworks impose limitations on charge transfer and the weak interlayer interactions in 2D COFs, adversely affecting the stability during switching processes. Herein, we introduced Ti knots to construct three-dimensional metalated covalent organic frameworks (3D MCOFs), denoted as Ti-DHTA-Py. The Ti knots not only serve as templates for organizing organic units into unique 3D topological structures in a controlled manner but also establish charge transfer pathways conducive to electron delocalization and transmission within the framework. As a result, the 3D Ti-DHTA-Py MCOFs electrode exhibited a reduced band gap and remarkable electrochromic (EC) performances: electrochemical cyclic stability of 93.6% retention after 500 cycles, switching times (2.5 s/0.5 s), and a high coloration efficiency (423 cm2 C-1). This research underscores the potential of 3D MCOFs as promising candidates for advancing EC technologies, surmounting the limitations associated with traditional 2D COFs.

Graphene quantum dots based flexible planar micro-supercapacitors with different bending angles

Graphene quantum dots based flexible planar micro-supercapacitors with different bending angles

Multifunctional electrochromic yarns for variable optical and thermal regulation

In this study, tungsten oxide and polyaniline hybrid films were deposited on the surface of stainless steel yarns by electrochemical deposition, and the electrochromic yarns with double electrochromic layer structure were formed. WO3 acts as a protective layer and binder to connect PANI nanorods, thereby improving electrochemical stability and electrochromic performance. The electrochromic yarns present five color changes in the voltage range of −0.4 V-1.1 V, the optical modulation of 59.98 %, the response time of 0.75 s, the coloration efficiency of 74.89 cm2/C, good electrochemical cycling stability (100 cycles without significant degeneration) and washing durability. At the same time, stable electrochromic behavior is still maintained in the bending state. The device based electrochromic yarns also has reversible multi-color variation, fast reaction time, and long-term stability. What's more, the device can be embroidered or woven into the fabric and designed into patterns of different colors. More color combinations can be achieved by adjusting the voltage. Finally, the fabric based on multifunction electrochromic yarns are used to study the thermal shielding performance. It can effectively block thermal radiation. These results indicate that the electrochromic yarn has promising potential for high-performance optical and thermal regulation applications. This research provides a prospective strategy for constructing multifunctional electronic devices in wearable application.

Electrochemical behaviour of ZrS2@rGO nanohybrid for high-performance supercapacitors

The batteries and capacitors have limited energy storage capacity due to reduced electrochemical performance and cycle stability. The existence problem can be overcome by fabricated nanostructured materials via enhanced electrical conduction and a significant surface area are essential for fulfilling the key requirements in evaluating as excellent electrode used in supercapacitors application, like as stability and extraordinarily high performance. This study utilises a cost-effective sonochemical approach to fabricate a ZrS2@rGO nanohybrid. The synthesized ZrS2 and ZrS2@rGO nanohybrid electrode were analyzed by their structural behaviour, oxidation state and morphological properties by utilising X-ray diffractometry (XRD), X-ray photoelectron spectroscopy and scanning electron microscopy (SEM) to verify the fabricated material. The addition of rGO sheets to ZrS2 particles enhances the surface area as well as capacitance of the ZrS2@rGO nanohybrid due to superior adsorption of electrolyte ions. The ZrS2@rGO nanohybrid demonstrated exceptional stability and attained the exceptional capacitance (Cs) of (1237.9 F/g) @ 1 A/g and the energy (68.5 Wh/kg), power density (Pd) of 315.7 W/kg during GCD (galvanostatic charge/discharge) analysis by utilising three-electrode setup. The ZrS2@rGO nanohybrid exhibits exceptional electrochemical properties, which proved to be an excellent material for their significant storage, unlike batteries and simple capacitors, as well as used as considerable potential for future technological advancements and energy storage devices.

Upcycling waste polyethylene terephthalate (PET) bottles into high-performance activated carbon for electrochemical desalination

Upcycling waste polyethylene terephthalate (PET) bottles has attracted intensive research interests. This simultaneously alleviates plastic pollution and achieves a waste-to-resource strategy. Waste PET water bottles were used to fabricate value-added activated carbon (AC) electrodes for capacitive deionization (CDI). The KOH activation temperature (greater than 700 °C) prominently affected the physi-chemical properties and desalination performance of PET-derived activated carbons (PET-AC). Profiting from a large Brunauer–Emmet–Teller specific surface area (1448 m2 g−1) with a good mesoporous structure (the ratio of the mesopore volume to the total pore volume was 41.3%), PET-AC-1000 (activated at 1000 °C) possessed a huge specific capacitance of 108 F g−1 for capacitive ion storage. Moreover, when utilized as the electrode material in single-pass CDI, PET-AC-1000 exhibited a maximum electrosorption capacity of 10.82 ± 0.11 mg g−1 and a low level of energy consumption (0.07 kWh mol−1), associated with good electrochemical charging-discharging cyclic stability. The results provide a promising facile approach to tackle the challenge of plastic pollution and promote the advancement of electrode materials for economic affordable and energy-efficient electrochemical desalination process, which meets the United Nations (UN) sustainable development goals (SDGs).

High-Performance All-Solid-State on-Chip Planar Micro-Supercapacitors Based on Aminated Graphene Quantum Dots by Photolithography

Rapid development of portable miniaturized electronic devices has put forward higher requirements for microenergy. Functionalized graphene quantum dots combine the properties of both functionalized graphene and quantum dots, and are expected to promote further development of high-performance energy storage devices. Here, all-solid-state on-chip planar micro-supercapacitors (PMSCs) were fabricated based on aminated graphene quantum dots by modified liquid-gas interface self-assembly and photolithography, with the electrode width/gap of 24 μm/8 μm. The electrochemical performance was analyzed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectrometry and cycle stability in PVA/H2SO4 gel electrolyte. The results indicated that the fabricated PMSCs showed good capacitive response at the scan rates of 0.01 V s−1 to 10000 V s−1. The CV curves of the PMSCs displayed a typical pseudocapacitive feature at the scan rates of 0.01 V s−1 to 1 V s−1. The PMSCs had ultrahigh rate capability of up to 10000 V s−1, and the GCD curves were near triangle-shaped curves, demonstrating excellent electrochemical reversibility. The PMSCs showed ideal capacitive behavior at the low frequency region of the Nyquist plot. The Nyquist plot of the PMSCs showed a semicircle at the high frequency region. The relaxation time constant of the PMSCs were 3.59 μs, indicating that the PMSCs had fast frequency response. After 10000 charge-discharge cycles at the scan rate of 500 V s−1, the initial capacitance retention rate of the PMSCs were 99.17%, indicating that the PMSCs possessed good long-term electrochemical stability. This study provides an important reference for the application of functional graphene quantum dots in the field of the PMSCs.

3D carbonaceous substrates synthesized from melamine sponges for energy storage: Influence of pyrolysis temperature in physicochemical and electrochemical properties

High-energy global requirements have caused a renewed interest in studying and developing new and improved energy storage devices and, precisely, the electrode materials that compose them, which play a fundamental role in determining the device’s performance. Carbon materials are first-class candidates due to their high electrical conductivity, chemical stability, and surface area. Although several carbon materials and their precursors have been studied, melamine sponges stand out for their nitrogen content, allowing them to act as a template and precursor for N-doped, ultralight carbon materials with good mechanical properties and a controlled pore size distribution. This work reports a simple and quick methodology to form ultralight and flexible carbon foam, along with the influence of the pyrolysis temperature on the physicochemical and electrochemical properties of 3D carbonaceous substrates used for energy storage and synthesized from melamine sponges. The substrates exhibit higher 3D porous structure than previously reported materials, with an average pore diameter of 80–90 µm. This morphology, added to the N content, promotes the remarkable electrochemical behavior (MS–950 °C) and cycling stability (MS–1000 °C) of almost 100% of capacitance retention after 10,000 cycles (≈ 60 F/g @1 A/g).

Elucidating mechanisms and DFT analysis of monometallic Vanadium incorporated nanoporous TiO2 as advanced material for enzyme-free electrochemical blood glucose biosensors with exceptional performance tailored for point-of-care applications

Diabetes is a chronic condition that can last a lifetime and has claimed a great number of lives in recent years. This motivated scientists to design a glucose biosensor to monitor and control blood glucose levels in diabetic patients. Herein, hydrothermal derived Vanadium (V), Nickel (Ni), and Cobalt (Co)-dopedTiO2 (MxTi1-xO2 (x = 0.01, 0.02, and 0.03)) was synthesized to achieve the best material to answer the pertaining problem. Of all the materials synthesized, V0.03Ti0.97O2@NF demonstrated the highest level of sensitivity, and selectivity, and has higher electrochemical cycling stability in 0.1 M KOH. It exhibits a very high sensitivity of 1129.31 μAmM-1cm-2 and Limits of Detection (LOD) and Limits of Quantification (LOQ) of 1.8 μM (S/N = 3) and 6.2 μM, respectively, with a broad linear range from 20 μM to 2 mM. The DFT approach was employed computationally to analyze the adsorption of glucose on surfaces of pure TiO2 and TiO2 doped with V, Ni, and Co respectively. The research findings highlight that when it comes to its interaction with glucose, pure TiO2 exhibits significantly less reactivity compared to transition metal-doped TiO2. Experimentally it shows thattheV0.03Ti0.97O2@NF surface has the most sensitiveglucose detection capability and it alsoexhibited significant selectivity towards glucose in the presence of additional interference. Itdemonstrated 100% retention after cycling stability and had a shelf life of ≃30 days. The V0.03Ti0.97O2@NF-based sensor exhibits accurate glucose sensing, even for human serum samples.

Superior Electrochemical Performance and Cyclic Stability of WS2@CoMgS//AC Composite on the Nickel-Foam for Asymmetric Supercapacitor Devices

Two-dimensional (2D) sulfide-based transition metal dichalcogenides (TMDs) have shown their crucial importance in energy storage devices. In this study, the tungsten disulfide (WS2) nanosheets were combined with hydrothermally synthesized cobalt magnesium sulfide (CoMgS) nanocomposite for use as efficient electrodes in supercapattery energy storage devices. The characteristics of the WS2@CoMgS nanocomposite were better than those of the WS2 and CoMgS electrodes. XRD, SEM, and BET analyses were performed on the nanocomposite to examine its structure, morphology, and surface area in depth. In three-electrode assemblies, the composite (WS2@CoMgS) electrode showed a high specific capacity of 874.39 C g−1 or 1457.31 F g−1 at 1.5 A g−1. The supercapattery device (WS2@CoMgS//AC) electrode demonstrated a specific capacity of 325 C g−1 with an exceptional rate capability retention of 91% and columbic efficiency of 92% over 7000 cycles, according to electrochemical studies. Additionally, the high energy storage capacity of the WS2@CoMgS composite electrode was proved by structural and morphological investigations.

Enhanced Electrochemical Performance and Cyclic Stability of Li-Ion Batteries by Employing Nanostructured Bi2Te3 Particles with Amorphous ZrO2 Nanocoating

Enhanced Electrochemical Performance and Cyclic Stability of Li-Ion Batteries by Employing Nanostructured Bi₂Te₃ Particles with Amorphous ZrO₂ Nanocoating

Nitrogen-doped Graphene/Natural Rubber and Sodium Dodecyl Sulfate Modified Nanocomposites: Study on the Electrochemical Properties for the Potential Sensor Response

In this study, a piezoelectric composite was developed based on nitrogen-doped graphene/natural rubber (NGr-NR) and an anionic surfactant sodium dodecyl sulfate (SDS) through a simple sonication method. Taking advantage of the high electrical conductivity and high surface area of NGr, the hybrid network of NGr-NR-SDS nanocomposite showed excellent mechanical properties and enhanced electrochemical behavior. Here, NGr was used as functional filler materials incorporated into NR polymeric matrix. SDS was used with NGr-NR composite to reduce the aggregation and promote the interfacial interaction between NGr-NR which enhanced the stability of sensor. The surface morphology of NGr-NR-SDS was investigated by field emission scanning electron microscopy, transmission emission microscopy, and Fourier transform infrared spectroscopy. Cyclic voltammetry and electrochemical impedance spectroscopy of NGr-NR-SDS showed the highest current response of 17 μA and the lowest Rct value of 1920 Ω demonstrating the excellent electrochemical response. The significance of this result is that the developed nanocomposite shows great potential for flexible piezoelectric devices due to excellent electrochemical response and cyclic stability.

Constructing low-cost stable zinc-ion batteries with sodium-rich monoclinic manganese hexacyanoferrate cathode

Manganese-based Prussian blue analogues are ideal candidate cathode materials for constructing high-voltage zinc-ion batteries. However, challenges have persisted in realizing envisioned highly stable electrochemical cycling systems due to manganese dissolution under aqueous conditions and self-corrosion of zinc metal anodes. Considering practical application demands and cost-effectiveness, non-aqueous organic zinc-ion batteries have shown significant development potential by avoiding interference from active hydrogen and offering a stable wide voltage window. Herein, a sodium-rich monoclinic structured manganese hexacyanoferrate (m-MnHCF) was synthesized via a simple coprecipitation method, achieving a stable high-voltage zinc-ion battery energy storage system in a diluted 0.2 M Zn(CF3SO3)2 electrolyte in acetonitrile, a non-protonic polar solvent. The battery exhibited a discharge specific capacity of 77 mAh g−1 at the current density of 1 A g−1 after 620 cycles. Furthermore, by circumventing interference from active hydrogen, a cost-advantaged zinc powder anode (Zn-P) was successfully introduced into the energy storage system. Assembled Zn-P||m-MnHCF cells exhibited stable cycling for 100 cycles at a current density of 0.5 A g−1 with close to 100 % coulombic efficiency, showcasing limitless possibilities for the future, as demonstrated by illuminated LED arrays.

Development of lignin hydrogel reinforced polypyrrole rich electrode material for supercapacitor and sensing applications

The preparation of natural polymer-based highly conductive hydrogels with reliable durability for applications in supercapacitors (SCs) is still challenging. Herein, a facile method to prepare alkaline lignin (AL)-based polypyrrole (PPy)-rich, high-conductive PPy@AL/PEGDGE gel was reported, where AL was used as a dopant, polyethylene glycol diglycidyl ether (PEGDGE) as a cross-linking agent, and PPy as a conducting polymer. The PPy@AL/PEGDGE gel electrode materials with hollow structures were prepared by electrochemical deposition and chemical etching method and then assembled into sandwich-shaped SCs. Cyclic voltammetry (CV), galvanotactic charge discharge (GCD), electrochemical impedance spectroscopy (EIS) and cycling stability tests of the PPy@AL/PEGDGE SCs were performed. The results demonstrated that the SCs can achieve a conductivity of 25.9 S·m−1 and a specific capacitance of 175 F·g−1, which was 127.4 % higher compared to pure PPy (77 F·g−1) electrode. The highest energy density and power density for the SCs were obtained at 23.06 Wh·kg−1 and 5376 W·kg−1, respectively. In addition, the cycling performance was also higher than that of pure PPy assembled SCs (50 %), and the capacitance retention rate can reach 72.3 % after 1000 cycles. The electrode materials are expected to be used as sensor and SCs devices.

Nanoflake Ni-MOF anchored octahedral nickel-porphyrins as a high-performance anode for lithium-ion batteries

Metal-organic framework materials (MOFs) have great potential as organic electrode materials for lithium-ion batteries due to their amiable porous structure and property tunability. However, the structure instability and poor electrochemical durability of MOFs hinders their application. An interesting metal–organic composite composed of Ni-MOF and Nickel (II)meso-Tetraphenylporphyin (NiTPP) is strategically proposed and configured in this study. The synergic integration of Ni-MOF and NiTPP presents a stable electrochemical cycling performance with a high retention capacity up to 840 mAh/g after 200 cycles, ascribed to the facilitation of the charge transfer capability and the diffusion kinetics. The configured metal–organic composites provide an explorative approach for organic alternatives for nonaqueous metal-ion batteries.

Recent Progress Using Graphene Oxide and Its Composites for Supercapacitor Applications: A Review

Supercapacitors are prospective energy storage devices for electronic devices due to their high power density, rapid charging and discharging, and extended cycle life. Materials with limited conductivity could have low charge-transfer ions, low rate capability, and low cycle stability, resulting in poor electrochemical performance. Enhancement of the device’s functionality can be achieved by controlling and designing the electrode materials. Graphene oxide (GO) has emerged as a promising material for the fabrication of supercapacitor devices on account of its remarkable physiochemical characteristics. The mechanical strength, surface area, and conductivity of GO are all quite excellent. These characteristics make it a promising material for use as electrodes, as they allow for the rapid storage and release of charges. To enhance the overall electrochemical performance, including conductivity, specific capacitance (Cs), cyclic stability, and capacitance retention, researchers concentrated their efforts on composite materials containing GO. Therefore, this review discusses the structural, morphological, and surface area characteristics of GO in composites with metal oxides, metal sulfides, metal chalcogenides, layered double hydroxides, metal–organic frameworks, and MXene for supercapacitor application. Furthermore, the organic and bacterial functionalization of GO is discussed. The electrochemical properties of GO and its composite structures are discussed according to the performance of three- and two-electrode systems. Finally, this review compares the performance of several composite types of GO to identify which is ideal. The development of these composite devices holds potential for use in energy storage applications. Because GO-modified materials embrace both electric double-layer capacitive and pseudocapacitive mechanisms, they often perform better than pristine by offering increased surface area, conductivity, and high rate capability. Additionally, the density functional theory (DFT) of GO-based electrode materials with geometrical structures and their characteristics for supercapacitors are addressed.

Fullerene Intercalation of MXene Toward Super‐Long‐Cycle Sodium Ion Storage

Abstract2D layered MXene‐based materials are applied as cation‐intercalation electrode materials for sodium‐ion batteries (SIBs) due to their layered structures but suffer from spontaneous restacking during Na+ insertion and deintercalation processes, resulting in sluggish reaction kinetics and poor cycling stability. Herein, fullerene C60 is intercalated covalently into the interlayer of Ti3C2Tx MXene nanosheets by using a low‐temperature hydrothermal reaction between a water‐soluble C60 derivative and hydrophilic MXene nanosheets, resulting in enlarged interlayer spacing of MXene nanosheets from 12.8 to 14.1 Å and consequently retarded self‐restacking. Moreover, the strong electron extraction ability of C60 facilitates electron transfer from MXene to C60, enabling faster charge transport during Na+ transportation. The as‐prepared C60@MXene hybrid is applied as a novel anode of SIBs, exhibiting outstanding electrochemical performance and super‐long cycling stability. C60@MXene‐based SIB delivers a specific capacity of 226.8 mAh g−1 at 0.1 A g−1 after 300 cycles, which surpasses that obtained from the pristine MXene anode, and retains 94.5% capacity at 1 A g−1 after 10 000 cycles. DFT simulations confirm that C60‐induced enlarged interlayer spacing benefits Na+ migrations, which is responsible for improved electrochemical performance and cycling stability.

Study on Tin-Cobalt Bimetallic Phosphide Nanoparticles as a Negative Electrode of Sodium-Ion Batteries.

Tin phosphide (Sn4P3) holds great promise because sodium-ion batteries use this material as an anode with impressive theoretical capacity. In this paper, it is reported that Co-doped Sn4P3 is embedded into carbon-based materials and SnCoP/C with a porous skeleton is prepared. As a result, SnCoP/C-2, as the material utilized in sodium-ion battery anodes, exhibits reversible capacities at 415.6, 345.9, and 315.6 mAh g-1 at current intensities of 0.5, 1.0, and 2.0 A g-1, respectively. The electrochemical reversibility, cycle stability, and rate performance of SnCoP/C samples are obviously better than those of Sn4P3/C. Cobalt in SnCoP/C stabilizes the conductive matrix of tin phosphide and promotes the diffusion kinetics of sodium. These results show that, with an appropriate amount of cobalt doping, highly dispersed nanoparticles can be formed in the tin phosphide matrix, which can significantly enhance the cycle stability of tin-based electrode materials.

Direct regeneration of spent LiFePO4 cathode material via a simple solid-phase method

For realizing the goals of “carbon peak” and “carbon neutrality”, lithium-ion batteries (LIB) with LiFePO4 as the cathode material have been widely applied. However, this has also led to a large number of spent lithium-ion batteries, and the safe disposal of spent lithium-ion batteries is an urgent issue. Currently, the main reason for the capacity decay of LiFePO4 materials is the Li deficiency and the formation of the Fe3+ phase. In order to address this issue, we performed high-temperature calcination of the discarded lithium iron phosphate cathode material in a carbon dioxide environment to reduce or partially remove the carbon coating on its surface. Subsequently, mechanical grinding was conducted to ensure thorough mixing of the lithium source with the discarded lithium iron phosphate. The reaction between CO2 and the carbon coating produced a reducing atmosphere, reducing Fe3+ to Fe2+ and thereby reducing the content of Fe3+. The Fe3+ content in the repaired LiFePO4 material is reduced. The crystal structure of spent LiFePO4 cathode materials was repaired more completely compare with the traditional pretreatment method, and the repaired LiFePO4 material shows good electrochemical performance and cycling stability. Under 0.1 C conditions, the initial capacity can reach 149.1 mAh/g. It can be reintroduced for commercial use.

Electrolyte solvent composition regulating endows CoSe2 hollow nanocage anode with stable potassium ion storage

Metal selenides are ideal anode materials for potassium-ion batteries (PIBs) due to their significant merits of favorable conductivity and ion transport property. However, the inevitable volume changes of metal selenides electrode during potassiation/depotassiation processes result in the fracture and reconstruction of the solid electrolyte interphase (SEI) layer, causing capacity decay and significantly limiting their practical applications. Reasonable morphology control accompanied by uniform and rigid SEI layer formation are key factors in improving the electrochemical cycling stability of metal selenides. In this paper, nano-hollow CoSe2 (CoSe2@CNC) anode materials are prepared using ZIF-67 as the precursor. The differences of electrochemical performances for CoSe2@CNC anode material in ester-based and ether-based electrolytes have been investigated in detail. Results demonstrate that the SEI layer formed in the ester-based electrolyte is loose and thick, leading to electrode pulverization and material detachment after several cycles, resulting in rapid degradation of cycle performance. In contrast, a thin and inorganic-rich SEI layer containing more inorganic components is formed in the ether-based electrolyte, effectively protecting the electrode from damage, facilitating electronic transfer at the electrode electrolyte interphase, and optimizing potassium ions storage performance.